1. Field
The present invention relates to a light emitting display device.
2. Description of the Prior Art
Among light emitting display devices, an organic light emitting display device is a self-luminous display device which has the features of a wide viewing angle, a superior contrast, and a high response speed, and thus has been in the spotlight as the next-generation display device.
An organic light emitting display device has an organic light emitting layer that is made of an organic light emitting material disposed between an anode electrode and a cathode electrode. When anode and cathode voltages are respectively applied to these electrodes, holes injected from the anode electrode move to the organic light emitting layer through a hole injection layer and a hole transport layer, and electrons move to the organic light emitting layer through an electron injection layer and an electron transport layer. In the organic light emitting layer, the electrons and the holes are recombined, and through this recombination, excitons are generated. As the generated excitons transition from an excited state to a ground state, the organic light emitting layer emits light to display an image.
Such an organic light emitting display device includes a pixel defining layer having an opening for exposing an anode electrode that is formed on each of pixels which are arranged on a substrate in a matrix form, and a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, an electron injection layer, and a cathode electrode are formed on the anode electrode that is exposed through the opening of the pixel defining layer. The hole injection layer, the hole transport layer, and the organic light emitting layer may be formed in the form of a thin film through discharging of ink into the opening of the pixel defining layer through a discharge head having at least one nozzle using an inkjet printing method or a nozzle printing method.